| Abstrakt: |
The characterization of fructose-1,6-bisphosphatase in stage VI oocytes from the frog Caudiverbera caudiverbera, as well as the in vivoactivity, is reported. The enzyme has a subunit molecular weight of approximately 43,500, has an apparent Kmvalue of 17 μM for fructose-1,6-bisP, and is inhibited by substrate concentrations beyond 100 μM. AMP and fructose-2,6-bisP are strong inhibitors of oocyte fructose-1,6-bisphosphatase activity with Kivalues of 9 and 2 μM respectively. Inhibition by AMP is cooperative with a nHvalue of 2.2. In vivofructose-1,6-bisphosphatase activity was demonstrated by microinjection of [U-14C]- or [6-32P]fructose-1,6-bisP and subsequent chromatographic separation and identification of labeled products. The relevance of these findings for the metabolism of glucose in frog oocytes is discussed. |
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